Preheat the oven to 180°C and line a 12-hole muffin trays with paper cupcake cases.
Sift together all-purpose flour, baking powder, and salt. Add the sugar and stir until thoroughly combined. Set it aside.
In a separate bowl, combine the hot water, vegetable oil, buttermilk, and vanilla. Add the egg and whisk together.
Make a well in the center of the flour mixture and add the wet ingredients. Slowly mix starting at the center until everything is combined.
Pour or spoon the batter into the liners. Fill each cup cake liner to about 3/4 full.
Bake for 20 minutes, or until a toothpick inserted in the center comes out clean. Allow to cool completely before frosting.
To make frosting, beat the butter until it looks fluffy. Gradually add 2 cups of confectioners' sugar and beat well.
Pour in the milk and vanilla, then slowly beat the remaining sugar. If the frosting feels too thick, add more milk.
Fill the piping bag with frosting
Pipe ghosts onto the cupcakes by outlining the outside edge of the cupcake, before circling into the center, and then squeeze the bag and gently pull up to make a mound.
Place candy eyes